Low oxygen release electrodes

Abstract

Electrodes, electrochemical cells having higher threshold oxygen-release energies, and methods of making the same are disclosed. The electrodes may be a nickel-rich cathode with up to 10% of a rare-earth element such as cerium. The rare-earth element may be added by doping during the manufacture of the cathode or by applying a coating on a surface of the cathode.

What is claimed is: 
     
         1 . An electrochemical cell comprising:
 a first electrode;   a second electrode having at least 50 wt. % nickel and at least 2.5 wt. % of a rare-earth element but no more than 10 wt. % such that the second electrode has a higher oxygen-release energy than a same electrode free of the rare-earth element; and   an electrolyte in contact with each of the first and second electrodes.   
     
     
         2 . The electrochemical cell of  claim 1 , wherein the rare-earth element is cerium. 
     
     
         3 . The electrochemical cell of  claim 2 , wherein the second electrode has at least 80 wt. % nickel. 
     
     
         4 . The electrochemical cell of  claim 3 , wherein the second electrode has at least 5 wt. % cerium. 
     
     
         5 . The electrochemical cell of  claim 3 , wherein the second electrode has at least 7.5 wt. % cerium. 
     
     
         6 . The electrochemical cell of  claim 2 , wherein the second electrode has 6-8 wt. % cerium. 
     
     
         7 . The electrochemical cell of  claim 6 , wherein the electrolyte is configured to transport lithium ions between the first and second electrodes. 
     
     
         8 . The electrochemical cell of  claim 7 , wherein the electrolyte includes a lithium salt. 
     
     
         9 . The electrochemical cell of  claim 3 , wherein the second electrode is a cathode. 
     
     
         10 . A vehicle comprising the electrochemical cell of  claim 1 . 
     
     
         11 . A cathode assembly comprising:
 an electrode having a lithium metal oxide with at least 80 wt. % nickel, and at least 7.5 wt. % but no more than 10 wt. % cerium, wherein the nickel and cerium are present at a surface of the electrode such that a threshold-release-energy for oxygen is at least 90 kJ/mol.   
     
     
         12 . The electrode of  claim 11 , wherein the cerium is present in a cathode coating. 
     
     
         13 . The electrode of  claim 12 , wherein the cathode coating is 1 to 100 nm. 
     
     
         14 . The electrode of  claim 11 , wherein the cerium is present as a dopant. 
     
     
         15 . The electrode of  claim 11 , wherein the nickel is present in a lithium metal oxide of nickel-cobalt-manganese, lithium-nickel-cobalt-aluminum, and/or nickel-cobalt-manganese-aluminum. 
     
     
         16 . The electrode of  claim 11 , wherein the surface is configured to facilitate reduction when arranged in an electrochemical cell. 
     
     
         17 . A method of making an electrode comprising:
 providing a cathode mixture of nickel and cobalt precursors;   adding one or more cerium precursors;   effecting co-precipitation of the precursors to form a precipitate;   mixing the precipitate with a lithium salt; and   forming an electrode having at least 80 wt. % nickel and 2.5 to 10 wt. % cerium.   
     
     
         18 . The method of  claim 17 , wherein the one or more cerium precursors includes cerium sulfate. 
     
     
         19 . The method of  claim 17 , wherein the electrode has at least 7.5% cerium. 
     
     
         20 . The method of  claim 17 , wherein the one or more cerium precursors includes a plurality of different cerium precursors.